Answer:
7. 25% of the merchants who purchase goods from Asia also purchase from Europe.
Step-by-step explanation:
I am going to say that:
A is the percentage of merchants who purchase goods from Asia.
B is the percentage of merchants who purchase goods from Europe.
We have that:

In which a is the probability that a merchant purchases goods from Asia but not from Europe and
is the probability that a merchant purchases goods from both Asia and Europe.
By the same logic, we have that:

Which of following statement is individually sufficient to calculate what percent of the merchants in the group purchase goods from Europe but not form Asia?
We already have B.
Knowing
, that is, the percentage of those who purchase from both Asia and Europe, we can find b.
So the correct answer is:
7. 25% of the merchants who purchase goods from Asia also purchase from Europe.